1. FIELD OF THE INVENTION
This invention relates to a method and apparatus for permanent disposal of hazardous waste and more particularly, to a method and apparatus for permanent disposal of hazardous waste using a borehole extending through a geopressured formation.
2. CROSS REFERENCE TO RELATED APPLICATION
The disclosure of this application is related to my prior application having the same title, now all abandoned, as follows:
______________________________________ Ser. No. Filing Date ______________________________________ 06/468,842 June 20, 1983 06/621,518 June 18, 1984 07/018,757 February 24, 1987 07 147/040 January 20, 1988 ______________________________________
3. DESCRIPTION OF THE PRIOR ART
Permanent disposal of hazardous waste, such as flammables, heavy metals, acids and bases and synthetic organic chemicals present difficult problems. The difficulties are especially acute in disposal of heavy metals (radioactive) waste. Many methods have been developed to provide a proper and safe disposal of hazardous waste without contaminating our natural resources. Various disposal methods include landfills, injection wells, incineration, ocean dumping, wastes exchange, and destruction through organisms ("superbug" method).
U.S. Pat. No. 4,335,978 to Mutch discloses a land fill disposal system. Rather than relying upon the subsurface formation itself to prevent fluid migration, a pair of spaced impermeable liners are employed to prevent fluid migration. The disclosed land fill is located above rather than below the subsurface water table for the area to preclude contamination.
Haynes et al U.S. Pat. No. 4,377,509 is entitled "Packaging for Ocean Disposal of Low-Level Radioactive Waste Material". A plurality of conventional 55 gallon metal drums are filled with the nuclear waste material and placed within a concrete shell. A filler material of asphaltic or a dry portland cement concrete is then used to fill the shell. Immediately prior to dumping in the ocean, water is introduced into the shell to activate the cement. In an alternate embodiment, the concrete is allowed to harden before dumping into the ocean.
U.S. Pat. No. 4,377,167 to Bird et al discloses two improved container materials for solid waste materials at an underground impervious stable rock formation. The prior practice had been to rely upon the insolubility of the radioactive elements to prevent migration of the radioactive waste material rather than containing the waste for a sufficient period of time to effect decay within the container. Bird's invention resides in forming a container out of a naturally occurring nickel alloy having proven superior aging characteristics.
The Upermann U.S. Pat. No. 4,316,814 is entitled "Seal For A Storage Borehole Accommodating Radioactive Waste and Method of Applying the Seal". The storage waste containers are lowered into the borehole formed in a salt formation in a stacked relationship. The seal of the borehole above the stored material prevents escape of the radioactive waste up the borehole.
The Klingle et al U.S. Pat. No. 4,252,462 is entitled "Chemical Land Fill" for disposal of waste water sludge. An impoundment area having a liquid impervious base and a perimeter dike is arranged to receive the waste water liquid therein. The sludge is dewatered and subsequently covered with an impervious layer.
The following patents to Gablin et al disclose systems for disposing of nuclear reactor effluent having mixed liquid and particulate matters: U.S. Pat. Nos. 4,196,169, 4,168,243, 4,056,362, 4,167,491, 3,986,977.
Geologists have characterized subsurface rock formations forming the earth's crust in various ways. One such classification has been to divide sedimentary rocks into two broad groups based on their pore-fluid pressures. These two mutually exclusive groups are labeled (1) hydropressures and (2) geopressures, and will be defined in this application as such. Hydropressure zones or formation have pore fluid pressures that are created by the effective weight of the overlying waters plus the back pressure of out-flowing waters. Geopressure formations or zones are created where the hydropressure rock is sealed in a confined geological container (geopressure cell) and is subjected to a geostatic pressuring source greater than hydropressures. The geostatic pressuring force source is the weight and temperature of the earth's crust with depth of burial. A classic example of a hydropressure-geopressure province is the Gulf of Mexico Salt Basin, which includes the Texas-Louisiana Cenzoic Salt Basin.
Hydropressure formations have leaks which enable flow or migration of the fluid pressure so over time they adjust to the hydropressure pressure for the depth. This is commonly referred to as normal pressure. Unlike hydropressures or hydropressure formations, geopressure formations are sealed. A geopressure seal is defined as a restriction to flow such that geopressures have not been dissipated between the time they were created in the geologic past and the present. By definition all geopressures or geopressure formations must have a geopressure seal. The block of the earth's crust that is sealed off and contains the geopressures is called a geopressure cell which is the definition adopted herein. To create a geopressure cell (a confined or enclosed container or reservoir), the surrounding earth crust formations must be effective as a seal at the top, bottom and all sides of the cell.
The geopressure cells or formations are sealed in regional fault blocks by shale layers and regional fault growths. Porosity is preserved in geopressure formation or zones due to the pore fluid pressure which is greater than the hydropressure for the same depth. They are sometimes called or referred to as abnormally high-pressure zones or formations in the petroleum industry.
For an in depth description of hydropressure geopressure formations and their characteristics and properties, see the article "Geopressures" by Charles A. Stuart which appears in the Supplemental Proceedings of the Second Symposium on Abnormal Subsurface Pressure presented Jan. 30, 1970 at Louisiana State University in Baton Rouge, La.
The encountering of geopressure zones when drilling for hydrocarbons or minerals presented substantial problems. In U.S. Pat. No. 3,399,723, to Charles A. Stuart (class 166 subclass 4) those drilling problems associated with encountering a geopressure formation are addressed, but not for the purpose of the present invention. From the standpoint of describing the present invention both hydropressure and geopressure formations are defined and explained at length in the Stuart patent. The problem of encountering the abnormally high pressure of the geopressure zone when the geopressure barrier seal (the transition or mutation zone) is broken or penetrated by the drill bit is described as a kick and the parameters of accommodating that pressure transition are addressed.
All of the above specifically mentioned or identified U.S. patents and the C. A. Stuart published article are hereby fully and specifically incorporated herein for forming part of applicant's written description as if their content had been set forth in full.